Introduce Browser Tools Interface

Issue: file names vs folders

Recode TabWatcher -> DOMWindowWatcher

I think we now pretty much understand TabWatcher, but it is still very heuristic and relies on Firefox idiosyncrasies that can change. Chromebug has its own watcher and even more guesses about the platform. Let's replace all of that with a clean abstraction for nsIXULWindow and nsIDOMWindow lifetime event notifications. Then put it in a SharedObject so we only need one per application and we have clearer API.

Issue: DOMWindowWatcher API

Ideally we would mimic/influence jetpack here, as they have a subset of the same problem.

Sandboxed Extension Loading

By re-applying the module loading technology we can create a jetpack-like environmental wrapper for Firebug extensions. The extensions would be slightly simpler because they would just be zip files. They would be slightly more robust, because they would be evaled in a scope that only contains Firebug.

Refactor debugger.js <-> firebug-service.js API

Ultimately we want debugger.js to split into a front-end and back-end, with the back-end implementing Crossfire's V8-like protocol. So a start is to shift work between debugger.js and firebug-service.js to be an V8-like API, and use firebug-service.js as an adapter between V8-like protocol and Mozilla jsd. (Note that JSDebugv2 aka js::dbg should have this kind of API).